linux-kernel - Re: [PATCH] memory: tegra: Remove calls to dev_pm_opp_set

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Message-ID: <36db9831-0d68-2502-ad64-5aab05b16974@gmail.com>
Date:   Fri, 22 Jan 2021 18:00:44 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Viresh Kumar <viresh.kumar@...aro.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>
Cc:     Vincent Guittot <vincent.guittot@...aro.org>,
        linux-kernel@...r.kernel.org, linux-tegra@...r.kernel.org
Subject: Re: [PATCH] memory: tegra: Remove calls to dev_pm_opp_set_clkname()

22.01.2021 09:00, Viresh Kumar пишет:
> There is no point calling dev_pm_opp_set_clkname() with the "name"
> parameter set to NULL, this is already done by the OPP core at setup
> time and should work as it is.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
> Dmitry, am I missing something obvious here ?

The dev_pm_opp_set_clkname() ensures that the OPP table has a clk
assigned to the table.

The _allocate_opp_table() ignores all clk_get() errors except the
-EPROBE_DEFER.

The opp_table->clk must be not a PTR_ERR for these memory drivers.

On the other hand, the memory drivers also do the devm_clk_get()
themselves, hence technically clk_get() of _allocate_opp_table()
shouldn't fail. But I'll need to take a closer look at the clk core, to
check whether clk_get() could fail for the implicit _allocate_opp_table().

Tegra124-emc driver also has dev_pm_opp_set_clkname(), BTW.